package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;

    @Autowired
    private IFollowService followService;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Override
    public Result queryBlogById(Long id) {
        Blog blog = getById(id);
        if (blog == null){
            return Result.fail("博客不存在");
        }
        queryBlogUser(blog);
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user == null) {
            // 用户未登录，无需查询是否点赞
            return;
        }
        Long userId = user.getId();
        String key = BLOG_LIKED_KEY + blog.getId();
        //判断用户是否点赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            isBlogLiked(blog);
            queryBlogUser(blog);
        });
        return Result.ok(records);
    }

    @Override
    public Result likeBlog(Long id) {
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
        //判断用户是否点赞
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());

        if (score == null){
            //没有点赞
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            if (isSuccess){
                //保存用户到redis中
                stringRedisTemplate.opsForZSet().add(key,userId.toString(), System.currentTimeMillis());
            }

        }else {
            //4.如果已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //4.2 把用户从Redis的set集合移除
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
             }
         }
        return Result.ok();
    }

    @Override
    public Result queryBlogLikes(Long id) {
        //Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
        // 1.查询top5的点赞用户 zrange key 0 4

        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty()) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);
        List<UserDTO> userDTOS = userService.query()
                .in("id", ids)
                .last("order by Field(id," + idStr + ")")
                .list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class)).collect(Collectors.toList());
        return  Result.ok(userDTOS);
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isOk = save(blog);
        if (!isOk){
            return Result.fail("发布失败！");
        }
        //保存到redis中
        //查询该作者的所有粉丝
        List<Long> ids = followService.lambdaQuery()
                .eq(Follow::getFollowUserId, user.getId())
                .list().stream()
                .map(follow -> follow.getUserId())
                .collect(Collectors.toList());
        //推送笔记给所有粉丝
        for (Long id : ids) {
            String key = RedisConstants.FEED_KEY + id;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        // 返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //获取当前用户
        Long userId = UserHolder.getUser().getId();
        //key
        String key = RedisConstants.FEED_KEY + userId;
        //查询收件箱中的数据 ZREVRANGEBYSCORE KEY MAX MIN LIMIT offset count
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 5);
        //非空判断
        if (typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int count = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            //获取id
            String idStr = typedTuple.getValue();
            ids.add(Long.valueOf(idStr));
            long time = typedTuple.getScore().longValue();
            //获取分数
            if (minTime == time){
                count ++;
            }else {
                minTime = time;
                count = 1;
            }
        }
        String idStr = StrUtil.join(",", ids);
        //根据id批量查询
        List<Blog> blogList = query()
                .in("id", ids)
                .last("order by Field(id," + idStr + ")")
                .list();
        for (Blog blog : blogList) {
            queryBlogUser(blog);
            isBlogLiked(blog);
        }
        //封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogList);
        r.setMinTime(minTime);
        r.setOffset(count);
        return Result.ok(r);
    }
}
